CH4/CO2 separation from biogas stream using porous hydrophobic ceramic hollow fiber membrane contactors

Experiments were performed to separate CO2 from biogas using a ceramic hollow fiber membrane contactor (HFMC). CH4/CO2 mixed gas (34.5% CO2, CH4 balance) and monoethanolamine (MEA) were used. The influence of operating conditions, such as the gas flow rate, liquid flow rate, L/G ratio, CO2 partial pressure, and module type, on the CO2 removal efficiency and CO2 absorption flux was evaluated. As the gas flow rate increased, the CO2 removal efficiency decreased, while the CO2 absorption flux increased. The maximum CO2 removal efficiency was 96% at a gas flow rate of 0.1Nm(3) h(-1) while the maximum CO2 absorption flux was 7.5x10(-3) mol center dot m(-2)center dot s(-1) at a gas flow rate of 1Nm(3) h(-1). Moreover, the CO2 absorption flux and CO2 removal efficiency could be increased by more than 20% using the high-flux module.